Abstract: In this study, headspace gas chromatography-mass spectrometry (HS-GC-MS) was used to accurately identify and quantify ethylene oxide and 2-chloroethanol in milk and dairy products (liquid milk, fermented milk, infant formula milk powder, and ice cream). The sample was diluted to a constant volume in a headspace bottle and balanced at 90 ℃ for 20 min, and the extract was separated on a DB-624 capillary column (60 m × 0.32 mm, 1.8 μm) with temperature programming. Ethylene oxide and 2-chloroethanol were detected using an electrospray ionization (ESI) source in the selected ion monitoring (SIM) mode. Quantitation was carried out using matrix-matched calibration curves. Good linearity was obtained in the range of 0.1–10.0 mg/L (R2 ≥ 0.99). The limits of detection of ethylene oxide and 2-chloropropanol in milk, fermented milk and ice cream were 0.12 and 0.60 mg/kg, respectively. At three spiked levels, the average recoveries of the two compounds were between 75.9% and 101.6%, with relative standard deviations (RSD) less than 10%. This method is precise and accurate, and can meet the requirements for the detection of milk and dairy products with a complex matrix.

Key words: ethylene oxide; 2-chloroethanol; milk and dairy products; headspace-gas chromatography-mass spectrometry

摘要： 采用顶空-气相色谱-质谱联用技术，实现对乳及乳制品（液态乳、发酵乳、婴幼儿配方乳粉、冰淇淋）中环氧乙烷和2-氯乙醇的准确定性和定量。样品于顶空瓶中经稀释定容后，90 ℃下平衡20 min，采用DB-624毛细管色谱柱（60 m×0.32 mm，1.8 μm）程序升温模式实现目标物色谱分离，质谱采用选择离子扫描模式对环氧乙烷和2-氯乙醇进行检测，基质匹配标准曲线法定量。结果表明：该方法在0.1～10.0 mg/L线性良好（R2≥0.99），环氧乙烷和2-氯乙醇在液态乳、发酵乳和冰淇淋中的检出限为0.12、0.60 mg/kg；在低、中、高3 个加标水平下，2 种化合物的平均回收率为75.9%～101.6%，相对标准偏差均小于10%。该方法精密度和准确度良好，且方法灵敏度高，满足乳及乳制品复杂基质中环氧乙烷和2-氯乙醇的检测要求。

关键词: 环氧乙烷；2-氯乙醇；乳及乳制品；顶空-气相色谱-质谱联用